Electrical control system for dual pumping apparatus



Feb. 14, 1939.

ELECTRiCAL CONTROL SYSTEM FOR DUAL PUMPING APPARATUS H M. WOOD ET ALFiled June 5, 1956 2 Sheets-Sheen l CONNECTION L'OST no T/ON/ OperaI/h Fnew 9 42 4e 33 r49 11 1) itt8 Q f8 50 J 48 @Mdm 4 5M H51"? y MWZM/ 3OFran/f LEE/557" Feb. 14, 1939. H. M. WOOD ET AL ,0

ELECTRICAL CONTROL SYSTEM FOR DUAL PUMPING APPARATUS Filed June 5, 1936I 2 Sheets-Sheet 2 Fig.

MECHANISM MECHFIN/SH TO BE TO BE OPERHTED OPERHTED 4e 5/ 6 f 0 Z OFIUX/L/HRY Qw PILOT SWITCH W OpERHT/NG I J, PILOT SWITCH J 6 L.- //-/Z"I LOST MOT/0N CONNECTION 30 fiarryMWam Frank L- 7*75/7z z7 PatentedFeb. 14, 1939 PATENT OFFICE ELECTRICAL CONTROL SYSTEM FOR DUAIi PUMPINGAPPARATUS Harry M. Wood, Baltimore, Md., and Frank L.

Fisher, Wauwatosa, Wis., assignors to Allen- Bradley Company,'Milwaukee,Wis., a corporation of Wisconsin Application June 5, 1936, Serial No.83,690

15 Claims.

This invention relates to the control of two electrically responsivedevices which are to be alternately operated upon successive occurrencesof a predetermined condition. It also contemplates operation of bothdevices in unison under certain circumstances such-as the continuance ofthe condition beyond a predetermined point.

It is an object of this invention to provide a control for the motors oftwo pumps so that the pumps ordinarily operate alternately, and undercertain circumstances operate in unison.

By way of general explanation, it is desirable in many situations tohave two pumps for ejecting liquids from a tank, sump, or otherreceptacle,

the pumps operating one at a time and in alternate manner, but capableof being simultaneously operated in case the capacity of one pump isinsuilicient to discharge the liquid as rapidly as it accumulates.

Heretofore, it has been customary to effect the desired alternatecontrol or operation of the motors by mechanical mechanism'coacting withthe floats which close the switches governing the operation of themotors. When the conditions under which these pumps operate are borne inmind, it becomes apparent that such a mechanical interlocking mechanismis not entirely reliable, and it is therefore a particular object ofthis invention to provide a control to effect the desired alternateoperation of the pump motors which is entirely electrical in operationand does not involve mechanical mechanism apt to become stuck orrequiring considerable manual attention.

Besides obviating the need for objectionable mechanical mechanisms withtheir attendant disadvantages and their necessity for constant manualattention, the present invention attains a degree of simplicity notpossible with the past systems of control.

The subject matter of this invention further contemplates a controlsystem which is fully automatic, positive in operation, and which doesnot require any manual attention whatsoever, except occasionalinspection.

With the above and other objects in view which will appear as thedescription proceeds, this invention resides in the novel construction,combination and arrangement of parts substantially as hereinafterdescribed and more particularly so defined by the appended claims, itbeing understood that such changes in the precise embodiment of thehereindisclosed invention may be made as come within the scope of theclaims.

The accompanying drawings illustrate two com- 55 pleteexamples of thephysical embodiment of the invention constructed according to the bestmodes so far devised for the practical application of the principlesthereof, and in which:

Figure 1 is a diagrammatic illustration of this invention applied to thecontrol of a dual pump- 5 ing system; and

Figure 2 is a similar diagrammatic view showing the general applicationof the invention.

Referring now particularly to the accompany-- ing drawings, the numeralsl and 2 designate the 10 two electric motors for driving the pumps (notshown). These motors are adapted to be connected across lines L L and Lupon closure of electromagnetically actuated starter switches 3 and 4,respectively, the circuits leading from the 15 lines through theswitches 3 and 4 to the motors being conventional and obvious from thedrawmgs.

The desired alternate operation of the motors I and 2, or more directly,the closure of their 20 starter switches 3 and 4, respectively, isinitiated and takes place at the dictation of a control switch 5, floatcontrolled to close when the float rises in response to a rising liquidlevel in the sump which the pumps (not shown) are designed 25 to empty.

In the event the accumulation of liquid within the sump is more rapidthan the capacity of one pump, the continued rise of the liquid level inthe sump lifts a second or emergency float 30 located at a higher levelthan the operating float controlling the switch 5, to close an emergencyfloat switch 6 which acts to cut in whichever pump is idle so thatthereafter both pumps operate until the liquid level drops below theemer- 35 gency float.

The manner in which the closure of the operating float switch 5 effectsalternate operation of the motors l and 2 will be first describedwithout regard to the functioning of the emergency float valve 8.

The starter switch 3, associated with motor I, is closed uponenergization of a relay l0, which controls switches ll, l2, l3 and H.

The closure of the motor starter switch 4 asso- 45 ciated with motor 2is eflfected directly upon the energization of a relay 20 controllingswitches 2|, 22, 23 and 24.

Upon closure of the operating float switch 5, either the relay ill or 20is energized; depending upon whether or not a third relay 30 isenergized or deener'gized. The relay 3!) has a maintaining switch 3! andtwo other switches 32 and-33 so connected'that when one is open, theother is closed, and vice versa.

When the switch 33 is closed, the closure of the operating float switch5 will effect energization of relay 20, and when the switch 32 isclosed, the

closure of the operating float switch 5 will effect energization of therelay l3.

These three relays I0, 20 and 30 are so electrically connected with eachother and with the operating float switch 5 and the starter switches 3and 4 as to eiiect the desired alternate functioning ofthe motors and 2.The specific connec tions will be described in the following recitationof the operation of the system.

Operation With the system at rest in the condition depicted in thedrawings, not any of the three relays are energized and the motorswitches 3 and 4 are both open. Likewise, the operating float switch 5is open. Upon closure of the operating float switch 5, relay 20 isenergized by the closure of the following circuit.

This circuit may be traced as follows-Starting with line L throughconductor 4| to one side of switch 5, through the switch to conductor 42which leads to one side of switch i3 of relay ID, continuing throughthis switch, which is closed by virtue of the deenergization of relayIt), to conductor 43, one branch of which leads to one side of closedswitch 33 of. relay .30, through switch 33 to conductor 44, and thus toone side of the solenoid of relay 20. The other side of the solenoid ofrelay 20 is connected to main line L through conductor 45.

The completion of the circuit just traced effects energization of therelay 20 closing its switches 2|, 23 and 24, and opening its switch 22.Closure of the switch 23 maintains the energizing circuit for the relay20 as followsz-Starting with line L the circuit is made by conductor 4|through float switch 5 and conductor 42 to one-side of switch l3,through conductor 43 to one side of switch 23, and from the other sideof switch 23 through conductor 44 to one side of relay 20. From theother side of relay 20, the circuit is continued through conductor 45back to line L 7 As a result of this operation of relay 20, the motorstarter switch 4 is closed and the relay 3!! is energized.

The energizing circuit for the starter switch 4 is as follows:-Againstarting with line L, this circuit is made by conductor 4| which leadsto one side of switch 24 which being closed continues the circuitthrough to conductor 46 leading to one side of-gthe solenoid of starterswitch 4, the other side of this solenoid being connected to line Lthrough conductor 45.

Energization of the relay 30 is efiected by the closure of the followingcircuit:-Again beginning with line L this circuit is made by conductor4| which leads to one side of switch ll of relay H), which switch beingclosed continues the circuit to conductor 41 leading to one side ofswitch 2|. Switch 2| is closed so that the circuit continues toconductor 48 which leads to oneside of the solenoid of relay 30 and alsoto one side of its retaining switch 3|. .The other side of the solenoidof relay 3!! is connected to conductor 45 and thus back to line L As therelay 3|] is energized, it closes its maintaining switch 3|, closes-itsswitch 32, and opens its switch 33. The closure of its maintainingswitch 3| maintains the relay 30 energized independently of the relay20. The manner in which this is effected is clear from the drawing, asone side of the solenoid of relay 30 is connected through conductor 45with line L while the other side of the solenoid oi relay 30 isconnected through conductor 48, the closed switch 3|, conductor 41,switch H, and conductor 4|, with line L The condition of the system atthis stage is as followsz-Operating float switch 5 is closed; relay 20is energized; relay 3!! is energized; and motor starter switch 4 isclosed so that motor 2 is operating. As the liquid level descends, thefloat controlling switch 5 drops until the switch 5 is open. Uponopening of the switch 5, the energizing circuit for the relay 20 isbroken so that the relay 20 drops open and as a consequence of itsswitch 24 opening, the circuit for the solenoid of motor starter switch4 is also opened, thus stopping motor 2.

At this point, the relays l0. and 20 are deenergized, the motor switches3 and 4 are open, but the relay 30 is energized by reason of itsmaintaining switch 3| being closed.

With the next successive rise of the operating float and the closure ofits switch 5, it is desired that the motor starting switch 3 shall beclosed and the motor starter switch 4 remain open to effect the desiredalternate operation of the pump fmotors. Upon closure of the floatswitch 5, the

relay 20 cannot be energized as switch 33 which must be closed tocomplete its energizing circuit is openin view of the energization ofrelay 30.

Closure of the float switch 5 does, however, close the energizingcircuit of relay ID. This circuit can also be traced along conductor 42to one side of switch 22 which is closed, then through conductor 49 toone side of switch 32, which is now closed. Passing through closedswitch 32, the circuit is continued along conductor 50 which leads toone side of the solenoid of relay Ill. The other side oi the solenoid ofrelay I is connected through conductor 45 to line L The circuit for thesolenoid of relay ID is thus complete and its energization is effected.

Upon the energization of the relay l0, its

switches II and Bare opened and its switches l2 and I4 are closed. Theclosure of the switch l2 maintains energization of the relay l0 throughthe following circuitz-Again beginning with line L, this circuit followsconductor 4|, float switch 5, conductor 42, closed switch 22, conductor49, closed switch l2, and conductor 50 to one side of the relay III. Theother side of the relay I0 is connected with line L through conductor45.

The closure of the switch |4 effects energization of the solenoid ofstarter switch 3, the circuit therefor being from line L throughconductor 4| to one side of switch |4 through switch l4 to conductorwhich leads to one side of. the solenoid of starter switch 3, and fromthe other side thereof'through conductor 45 to line L Motor is thus setin operation.

The energization of relay I0, specifically the opening of its switchalso efiects deenergization oi. relay so as theclosure of switch II isnecessary to the maintenance of its energizing circuit. The opening ofswitch II is delayed by any suitable means as the provision of a lostmotion connection between it and its actuator to With the system in thenow established condition, operating float switch 5 is closed; relay I0is energized; starter switch 3 is closed, so that motor I is operating,while relays 20 and 30 are deenergized.

Upon reopening of the operating float switch 5 as a result of thelowering of the liquid level effected by the operation of the pumpdriven by motor I, the energizing circuit of relay I0 is opened inasmuchas the closure of switch 5 is necessary to maintain the energizingcircuit of relay l0.

. Upon the deenergization of the relay In, its

switches II and I3 are closed, and its switches l2 and I4 opened so thatthe system is again restored to its initial condition ready for the nextcycle.

Dual operation of motors for emergency purposesswitch 5. This switch S,as shown, is connected directly across the solenoids of the starterswitches 3 and 4 by conductors 4B and 5!.

Assuming that the starter switch i is closed and the motor 2 is inoperation, the closure of the switch 6 would initiate the operation ofmotor l as follows:-One side of the solenoid of motor starter switch 3is connected to line L through conductor 45. The other side of thesolenoid is connected through conductor ti to one side of emergencyfloat switch c. Tue other side thereof is connected by conductor th toswitch 24, and the other side of switch i l is connected throughconductor it to line L An energizing'circuit for the solenoid of starterswitch 3 is thus completed and will remain so until the switch 6reopens.

In the event that motor i is in operation and the emergency calls torthe action of motor 2, closure of the emergency float switch will effectclosure of energizing circuit for the solenoid of starter switch t as ioilowsa- Again beginning with line L conductor leads to one side or" thesolenoid or motor starter switch t, the other side thereof beingconnected through conductor 36 to one side of switch 6 which continuesthe circuit through the con ductor iii to then closed switch i l. I.opposite side oi @lflzicfl switch i l, the circuit completed throughcon-doctor li, which leads each to line As pointed out hereinheiore,this inv not restricted to the control or ethe elec tors of a dualpumping apparatus, but more general and broader application, shown inFigure 2. in this embodiment of the tion, the pilot switches 23 and 6shown as conventional switches not necessarily operated by floats, butcagoahle of actuated icy any *irne mover such as a pressure responsiveeielt, a thermostat or any other srdtah-le The eleotromagnets ti and tiobviously may actuate any mechanism to he controlled whicn is operableby electromagnets. Where the oreviously described application of theinvention sne-= ciflcally contemplates the control of electric inotors,these units may be readily replaced by valves, mechanical motiongenerating devices, or any other devices.

has a From the foregoing description taken in connection with theaccompanying drawings, it will be readily apparent to those skilled inthe art, that this invention provides a control for the alternate andalso concomitant energization of two electromagnets controllingmotorswitches or any other mechanism actuatable by electromagnets, which isentirely electrical, incorporating no mechanical switch-over mechanism,and one which requires no manual attention and is entirely dependableand automatic in operation.

What we claim as our invention is:

1. In combination with two main switches for starting electric motorsand the like, a single control switch, and an electric control systemconnecting the control switch with said two main switches so thatsuccessive closures of the control switch effects alternate closure ofthe two main switches, said system including a relay energizedconcomitantly with the closure of one main switch and deenergizedconcomitantly with the closure of the other main switch, said relayhaving switch means for determining which of the two main switches is tobe closed in response to closure of the control switch.

2. In combination with two main electromagnetic switches, a singlecontrol switch and an electric control system connecting the controlswitch with said two main electromagnetic switches so that successiveclosures of the control switch efiects alternate closure of the two mainswitches, said control system including two relays, one associated withone main switch and the other associated with the other main switch insuch a manner that energization of the relays efiects the closure oftheir associated main switches, a third relay having switch means fordetermining which of the two main switches is to he closed in responseto closure of the control switch, said third relay being biased to oneposi tion and electromagneticahy movable to its other position, andcircuit arr ernents interconnect the switches oi the st two relays withsaid third relay so third isv energized concomitantly with energizationone cleaner-sized concomitantly wi h the energization of the other ofsaid two i and on leg two that access alt electr :iagn ng two relayseach closure switches, said system co gmation oi the l two relays hmagnetic r e upon sure of the control switc ans autos c, ally on eraiileallow of. relays to ener izesl at est cite,

ene gization of said. i our s of the con sol ing a standard eiectio eticrelay i" the armature movable sw ments are biased to one position andelectromagnetically held the other position, and said standard relaybeing energised concomitantly with the closure of one main switch andcleanergized concomitantly with the closure of the other I main switch.

4, In combination with a'plurality oi main a ectrornog means conepris=matic switch for automatically determining which of said automaticswitches is to be closed upon closure of the control switch.

5. An electrical control system of the character described comprisingtwo electromagnets,

a controlling switch associated with each of said electromagnets, apilot switch adapted to be automatically closed, relays for controllingthe two controlling switches, means for energizing the relays uponclosure of the pilot switch, and

' an electrical automatic switch-over means for preventing simultaneousenergization of. said two relays upon closure of the pilot switch andauto- -matically operable to effect alternate energization thereof uponsuccessive closures of the pilot switch, said switch-over meansincorporating a relay, and means for controlling energization of saidrelay from said first two mentioned relays so that said last named relayis energized when one of said first two relays is energized and isdeenergized when the other of said first two relays is energized. V

6. In combination with two translating devices, a pilot switch and anelectric control system connecting the pilot switch with said twotranslating devices so that successive closures of the pilot switcheffects alternate operation of the two translating devices, said systemincluding a relay energized concomitantly with the operation of onetranslating device and deenergized concomitantly with the operation ofthe other translating device, said relay having switch means fordetermining which of the two translating devices is to be operated inresponse to closure of the pilot switch.

7. In combination with two translating devices, a pilot switch and anelectric control system connecting the pilot switch with the twotranslating devices so that successive closures of the pilot switchefiects alternate operation of the two translating devices, said controlsystem including two relays, one associated with one translating deviceand the other associated with the other translating device in such'amanner that functioning of the relays efiects operation of theirassociated translating devices, and a third relay energizedat thedictation of one of. said first two relays and deenergized concomitantlywith the energization of the other of said two relays,

said third relay being operable to determine.

which one of the first mentioned two relays will be energized uponclosure of the pilot switch..

8. In combinationfiwith two electromagnets, a pilot switch and anelectric control system connecting the pilot switch with the twoelectromagnets so that successive closures of the pilot switch effectsalternate energization of the two electromagnets, said control systemincluding a first relay associated with one electromagnet and a secondrelay associated with the other electrogized by the opening of a switchof the second relay, the third relay having switch means adapted whenthe third relay is deenergized to cause energization of the first relayupon closure oithe pilot switch and having other switch means adaptedwhen the third relay is energized to cause energization of the secondrelay upon closure of the pilot switch, and said switch of thesecondrelay which controls the deenergization of the third relay operatingwith a delayed action so as to insure energization of said second relaybefore the deenergization of. the third relay.

9. In combination with two electromagnets, a main pilot switchresponsive to a predetermined condition, an electric control systemconnecting the pilot switch with said two electromagnets so thatsuccessive closures of the pilot switch in response to successiveoccurrences of'the predetermined condition efiects alternateenergization of the two electromagnets, said system including a relayenergized concomitantly with the energization of one electromagnet anddeenergized concomitantly with the closure of the other electromagnet,said relay having switch means for determining which of the twoelectromagnets is to be energized in response to closure of the pilotswitch, and an auxiliary pilot switch connected in the system andoperable upon the continuance beyond a predetermined point of thecondition closing the main pilot switch for efiecting energization ofwhichever electromagnet is then deenergized.

10. An electric control system comprising two electromagnets, anoperating pilot switch adapted to be automatically closed upon theoccurrence of a predetermined condition, an auxiliary pilot switchadapted to be automatically closed upon the continuance beyond apredetermined point of said condition, electric circuits connecting thepilot switches with the electromagnets, and relays connected in saidcircuits, there being one relay for each of the two electromagnets socons be energized upon response of one of said first two relays anddeenergized upon response of the other of said two relays, said otherrelay having switches for determining which of the first two relays isto respond to closure of the operating pilot switch, and said auxiliarypilot switch being so connected with the electromagnets through saidcircuits and switches of said first two relays as to effect energizationof whichever electromag net is deenergized upon closure thereof.

11. In combination, a plurality of translating devices, a pilot switch,an electromagnetically actuated relay for each translating deviceadapted to be energized to initiate the operation of its translatingdevice, an additional relay, anv electric circuit connecting thetranslating devices,

the pilot switch and the relays for controlling the translating devicesfrom the pilot switch, said additional relay being energizedconcomitantly with the energization of one of said two relays anddeenergized concomitantly with the energization of the other of said tworelays to shift the control of the pilot switch from one to the other ofsaid translating devices.

12. In combination with two electromagnets, a pilot switch and anelectric control system connecting the pilot switch with the twoelectromagnets so that successive closures of the pilot'switch effectsalternate energization of the two electromagnets, said control systemincluding a first relay associated with one electromagnet and a secondrelay associated with the other electromagnet, said first and secondrelays having switches, and a third relay energized at the dictation ofa switch of the first relay and deenergized by the'opening of a switchof the second relay, the third relay having switch means adapted whenthe third relay is deenergized to cause energization of the first relayupon closure of the pilot switch and having other switch means adaptedwhen the third relay is energized to cause energization of the secondrelay upon closure of the pilot switch.

13. An.electrical control system, comprising a source oi E. M. F., twomain electromagnets, a pilot switch, three standardtw'o positionelectromagnetic relays, each having its armature and associated switchesbiased to one position and electromagnetically held in the otherposition, and circuit arrangements interconnecting the mainelectromagnets, the pilot switch, and the three standard relays with thesource of E. M. F. in such a manner that successive closures of thepilot switch alternately energize ;two of said standard relays toalternately effect energization of the main electromagnets andalternately energize and deenergize'the third relay upon successiveclosures of the pilot switch, and switch means actuated by said thirdrelay and so con- ;nected in said circuit arrangements as to alternatelyshift the control of the pilot switch from one to the other of saidfirst two mentioned relays.-

14. In a control system or the character described, a source of E. M. E,a pilot switch, a

first electroresponsive device, a second electroresponsive device, saidfirst and second devices having switches, a third electroresponsivedevice, and circuit arrangements interconnecting said pilot switch andsaid electroresponsive devices with the source of E. M. F. so that saidthird device is energized at the dictation of a switch of the firstdevice and deenergized by the opening of a switch of the second device,the third device having switch means adapted when said third device isdeenergized to cause energization of the first device upon closure ofthe pilot switch and having other switch means adapted when the thirddevice is energized-to cause energization of the second device uponclosure of the pilot switch.

15. In combination with two main switches for starting electric motorsand the like, a single control switch, and an electric control systemconnecting the control switch with said two'main switches so thatsuccessive closures of the control switch effect alternate closure ofthe two main switches, said system including one single coil twoposition relay energized concomitantly with the closure of one mainswitch and maintained energized after opening of said main switch toeffect closure of the other main switch upon the-next subsequent closureof the control switch and to be. deenergized upon closure of said othermain switch and to remain deenergized after opening of saidother mainswitch to restore the controlsystem to its initial condition at whichclosure of the control switch effects closure of the first designatedmain switch.

HARRY M. WOOD.

FRANKLFISHER. 35

